1. Field of the Invention
The present invention relates to electric starters intended for starting internal combustion engines, and it concerns more particularly the rotational driving of the drive pinion unit.
2. Description of the Prior Art
In conventional starters the armature of the electric motor is fastened against angular movement on a shaft, which in turn is provided with generally helicoidal splines permitting the rotational driving of the drive pinion unit. The shaft therefore takes the entire driving torque, so that it must be made with particular care. It is first of all necessary to select a high-strength steel capable of being treated before its main parts are ground. In addition, in the production of the shaft care must be taken to avoid the risk of fracture at the point where changes of diameter occur. Finally, the driver of the drive pinion unit is completely machined so that its cost is high.